                       options
                       (safe-fns options))
 
-        display           (or (:display options) 0)
-
         options           (merge (dissoc options :features)
                                  features)
 
+        display           (let [d (:display options)]
+                            (if d [d] []))
         size              (process-size (:size options) display)
+
         title             (or (:title options) (str "Quil " (swap! untitled-applet-id* inc)))
         renderer          (or (:renderer options) :java2d)
         draw-fn           (or (:draw options) no-fn)

                                  :draw-fn draw-fn
                                  :renderer renderer
                                  :size size
                                  :display display
                                  :target-frame-rate (atom 60)}
                                 listeners)
        prx-obj           (quil.Applet. applet-state)]

  "Checks that the size vector is exactly two elements. If not, throws
  an exception, otherwise returns the size vector unmodified."
  [size display]
  (cond (= size :fullscreen) (apply display-size display)
        (and (coll? size) (= 2 (count size))) size
        :else (throw (IllegalArgumentException.
                      (str "Invalid size definition: " size ". Was expecting :fullscreen or 2 elements vector: [x-size y-size].")))))
